Fennel and Citrus Tuna Tartare Bites

Ingredients

• • 1/2 cup (70 g) fennel bulb, cut into small dice
  • 3 tbsp (45 ml) olive oil
  • 1 red or pink grapefruit
  • 7 oz (200 g) very fresh red tuna
  • 1 tbsp chives, finely chopped
  • 1 lime, zest finely grated
  • 2 tsp (10 ml) lime juice
  • 1 tsp (5 ml) Worcestershire sauce
  • 1/2 tsp (2.5 ml) Tabasco-style sauce, or more to taste
  • 24 crispy hors-d’œuvre shells (such as Siljans)
  • Fennel fronds (optional)